Re: [Bugme-new] [Bug 16120] New: Oops: 0000 [#1] SMP, unable to handle kernel NULL pointer dereference at (null)

[Eric Dumazet <eric.dumazet@gmail.com>]

Le samedi 05 juin 2010 à 11:34 +0200, Eric Dumazet a écrit :
> Le samedi 05 juin 2010 à 11:17 +0200, Eric Dumazet a écrit :
> > Le vendredi 04 juin 2010 à 16:17 -0700, Andrew Morton a écrit :
> > > (switched to email.  Please respond via emailed reply-to-all, not via the
> > > bugzilla web interface).
> > > 
> > > On Fri, 4 Jun 2010 09:25:58 GMT
> > > bugzilla-daemon@bugzilla.kernel.org wrote:
> > > 
> > > > https://bugzilla.kernel.org/show_bug.cgi?id=16120
> > > > 
> > > >            Summary: Oops: 0000 [#1] SMP, unable to handle kernel NULL
> > > >                     pointer dereference at (null)
> > > >            Product: Platform Specific/Hardware
> > > >            Version: 2.5
> > > >     Kernel Version: 2.6.35-rc1
> > > >           Platform: All
> > > >         OS/Version: Linux
> > > >               Tree: Mainline
> > > >             Status: NEW
> > > >           Severity: high
> > > >           Priority: P1
> > > >          Component: x86-64
> > > >         AssignedTo: platform_x86_64@kernel-bugs.osdl.org
> > > >         ReportedBy: alex.vizor@gmail.com
> > > >         Regression: Yes
> > > > 
> > > > 
> > > > Created an attachment (id=26647)
> > > >  --> (https://bugzilla.kernel.org/attachment.cgi?id=26647) id)
> > 
> > > > 2.6.35-rc1 kernel log
> > > > 
> > > > It happens randomly, almost a week I used 2.6.35-rc1 and don't have any
> > > > problems. But since last day it happened twice.
> > > > 
> > > > I attached kernel log, please inform me if I can help in investigation.
> > > > 
> > > 
> > > ip6mr_sk_done() oopsed.
> > 
> > Only thing I found a first glance is a typo but this should not be the
> > root of the problem.
> > 
> 
> At a second glance, I think the problem is that we probably cleanup 
> in the wrong order.
> 
> ip6mr_rules_exit() is probably called before icmpv6_sk_exit() ?
> 
> I dont know how to fix this order, no more time for me until Monday.
> 
> 
> We should reinit mr6_tables list in ip6mr_rules_exit() in any case
> 
> 
> [PATCH] ip6mr: fixes
> 
> 1) Fix a typo in ip6mr_for_each_table() definition
> 
> 2) Re-initiliaze mr6_tables in ip6mr_rules_exit()
> 
> bugzilla report : https://bugzilla.kernel.org/attachment.cgi?id=26647
> 

Ah well, crap... https://bugzilla.kernel.org/show_bug.cgi?id=16120

Sorry, I really have to run...

> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
> 
> diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
> index 073071f..e2ff192 100644
> --- a/net/ipv6/ip6mr.c
> +++ b/net/ipv6/ip6mr.c
> @@ -120,7 +120,7 @@ static void mroute_clean_tables(struct mr6_table *mrt);
>  static void ipmr_expire_process(unsigned long arg);
>  
>  #ifdef CONFIG_IPV6_MROUTE_MULTIPLE_TABLES
> -#define ip6mr_for_each_table(mrt, met) \
> +#define ip6mr_for_each_table(mrt, net) \
>  	list_for_each_entry_rcu(mrt, &net->ipv6.mr6_tables, list)
>  
>  static struct mr6_table *ip6mr_get_table(struct net *net, u32 id)
> @@ -256,6 +256,7 @@ static void __net_exit ip6mr_rules_exit(struct net *net)
>  
>  	list_for_each_entry_safe(mrt, next, &net->ipv6.mr6_tables, list)
>  		ip6mr_free_table(mrt);
> +	INIT_LIST_HEAD(&net->ipv6.mr6_tables);
>  	fib_rules_unregister(net->ipv6.mr6_rules_ops);
>  }
>  #else
>